With `reveal_stragegy=always` + `reveal_target=center`,
`TerminalPanel::spawn_task` activates & focuses the pane of the task.
This works fine in the terminal pane but doesn't for
`reveal_target=center`.

Please note: I'm not verified familiar with the architecture and
internal APIs of zed. If there's a better way or if this fix is a bad
idea, I'm fine with adapting this 😃

Closes #35908

Release Notes:

- Fixed task focus when re-spawning a task with `reveal_target=center`

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>